An international
study shows that droughts in the Sahel region on the
southern Sahara rim can be affected by cyclical changes in
atmospheric pressure and sea surface temperature in the North
Atlantic Ocean.

Researchers
from Columbia University, the University of Haifa, the University of
San Diego, and the French National Meteorology Service studied how
climate variability in one location can affect another distant
location, and more importantly, were able to locate these
"far-connections" and "understand their projections."
Their study was published in the scientific journal Atmospheric
Science Letters.

The
study analyzed a number
of climate parameters in the North Atlantic which included
sea surface temperature and atmospheric pressure at sea level. This
research led them to discover two "natural climate signals,"
which consists of a multi-decadal signal of a period exceeding 40
years and a quasi-decadal signal with periodicity ranging from 8 to
14 years.

The
researchers, unsure as to whether these signals will enhance or
cancel one another out, compared them with "climatic
fluctuations as observed in coral and tree-ring studies, by which the
temperature values of the past few hundred years can be
reconstructed." According to the study, the signals were also
identified.

This
led the scientists to search
for a correlation between the droughts in the Sahel region
and the cyclical waves. The result was that when the Atlantic cools,
there are droughts in the Sahel region; and when the Atlantic's
temperature rises, it rains in the Sahel region.

This
isn't the first we've heard of these droughts
in the Sahel region though. From the 1970's through 1990's,
this region suffered from civilian desertion, starvation and other
environmental and social crises. In addition, the UN stated in
2007 that the situation in Darfur was "intensified by the
ongoing drought in the Sahel region and its surroundings."

According
to Dr. Shlomit Paz, a co-author in the study who works for the
Department of Geography and Environmental Studies at the University
of Haifa, this study
is an important addition to what science already knows about
climatic models, and is "improving their prediction
capability."

"Today
we are able to gain a better understanding of how the oceans play an
important role in the Earth's 'climate memory,'" said Paz. "Once
we become familiar with the natural signals, we will be able to
better understand how the human factor correlates with climate."